Extracts from a GCHQ’s internal GCWiki, last accessed in 2012, describe some of the privacy implications of the agency’s Optic Nerve tool: see the Guardian article Optic Nerve: millions of Yahoo webcam images intercepted by GCHQ, 28 February 2014.

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﻿Metadata:
• At the moment OPTIC NERVE’S data supply (run by B13) does not select but
simply collects in bulk, and as a trade-off only collects an image every 5 minutes.
...

These extracts from a GCHQ report from December 2008 describe the development and privacy implications of OPTIC NERVE, a tool that has enabled the agency to gather images from millions of webcams: see the Guardian article Optic Nerve: millions of Yahoo webcam images intercepted by GCHQ, 28 February 2014.